Sunroof exploded this morning.

I posted this on the other forum because they had a thread started. Driving to work this morning, exiting the highway, doing 45 mph, no other cars around. Then I heard this loud explosion, sunroof shattered.

72 degrees out,windows closed, sunroof closed. The thing shattered out wards. Strange.

It's goin in on Tuesday.

Wow. Haven't heard that in a while.

This better be a safety recall (NHTSA)...

"Sunroof exploded" has 9 pages of responses. So something is definitely a miss.

Sounds like either something struck it hard or there was a major temperature differential between inside and out????

I've seen a front window screen pop due to sudden change in differential temp.

good to see your cover was closed

Nothing hit it. It exploded out wards. That I'm sure of. Professionally speaking.

Could be temp variants cold outside and hot inside the car the only thing that comes to mind but DEFINITELY a major concern w me also although I live in Puerto Rico its the inverse of frisco guy

Sent from my SPH-L710 using BimmerApp mobile app

I bet that there was a flaw of some sort in the glass. A delta T would only be like 75 inside and say 45 or 50 outside. So this would be 25 to 30°F differential. This by itself would not create that high of a stress. Something else perhaps created a stress concentrator. A remember a guy at work that had a mid 1980's RX7 with the big back glass hatch. Real hot day in Houston and it shattered. The delta T was the opposite direction though. I wonder how much a sunroof replacement is? This isn't something a glass company would do. I'm thinking the whole part frame and all is what would be replaced. A long time ago, I was getting a window tint done on a Toyota Avalon and asked about getting the sunroof tinted too and they said no. They said they don't do them as concern for the sunroof exploding. Makes sense as typically when it is hot summer we have the inner cover closed. So, there alot more entrapped heat by the glass. If you tint, the filter is at the bottom of the glass so the heat and light stays in the glass instead of coming through.

Sorry, I always think the thermal things through about 3 layers deeper than normal people. Heat transfer on the brain will distort your thinking :-).

Looks like front windshields are layered safety glass while sides and sunroof are tempered. Reading about tempered glass it already has many fine invisible crack lines so it may not take that much to make it shatter.

Just an FYI. This was a common issue with early E90's. I'm talking 2006-2008 .

Originally Posted by BMWTurboDzl

Just an FYI. This was a common issue with early E90's. I'm talking 2006-2008 .

Indeed: http://www.bimmerfest.com/forums/sea...rchid=20446167

Originally Posted by floydarogers

Indeed: http://www.bimmerfest.com/forums/sea...rchid=20446167

This link doesn't work...

PL

Sorry, worked when I first tried it.

Go to E9x forum (tree at top, or drop-down box at lower right.)
Use "Search Forum" with terms "sunroof explosion"

I remember back when I had my 02 MCS and in the forums they had similar explosions but it was attributed mostly to people putting tint paper and that was a no no, I tried to put the tint on my car and the tint guy said NO WAY!! I asked the dealer at the time and they HIGHLY DID NOT reccomend to do it cause it would void warranty.

I hope that doesn't happen on my X5 Panoramic sunroof!

Here's the latest. I dropped it off at the dealership yesterday. The service advisor seemed to imply it was a frequent event.
"Mostly on the 5 series we see this"

They took my keys and that was about it. With the lack of questions, and the shaking of heads I would say it happens more than we know.

This is the nature of tempered automotive glass.

As others have mentioned, tempered glass is constantly in tension, pretty much the interior squeezing against the exterior, this is the source of its strength. As such, it can be considered brittle, it is very sensitive to shocks, whether physical or temperature, and inherently has spots which are weaker than others, typically at the edges, the surface near corners, and anywhere there is a deviation from either flat or a smooth, cylindrical curve.

Other factors to consider include overall size (bigger means more weak spots, more risk of stress from the glass supporting its own weight), perspective (a long rectangle has more perimeter than a square), and angle acuity (more acute angles are less stable).

In an automotive application, a sunroof has a few other factors against it: most are bonded into frames, which while providing (if properly fitting) torsional support, also absorb and release heat at a distinct rate, producing stress almost exactly where you don't want it (the edge). The (usual) dark glass used in sunroofs doesn't help on this front either, along with the extra heat absorption of facing relatively directly towards the sun all day. Finally, there is the inevitable bouncing which accompanies a glass which is not fixed to the car's body. Some of this also explains why backglasses are prime 'exploders' as well.

As for defects...well raw automotive float glass is a pretty consistent product, and after it is cut, bent, and tempered, there is a visual (possibly robotic) check of the tempering pattern, but that is pretty much it. If a glass breaks/explodes before it is installed in the car, I guess it would be deemed 'defective' (we certainly deemed it so, when a broken glass was discovered in the middle of a 100-piece crate), and you may get some sympathy from the dealer (good luck...) or manufacturer if it breaks within perhaps 90 days of purchase...but the truth is that Every piece of tempered glass manufactured is doomed to explode at some point, either sooner or later (so to speak), and pretty much all of the time nobody knows the proximate cause unless it is an obvious impact (often clear from the break pattern, if the glass is still intact after breaking). This is simply the nature of the product, and while it means it is an inferior product for some applications, this does not mean the the individual exploding piece is considered defective.